add list operators, code refactoring, change to gradle

.gitignore

@@ -88,4 +88,7 @@ hs_err_pid*
 
 target
 .idea
-querycompiler.iml
+querycompiler.iml
+
+build
+.gradle

build.gradle.kts

@@ -0,0 +1,39 @@
+plugins {
+    java
+    antlr
+    id("maven-publish")
+}
+
+group = "dev.gruen"
+version = System.getenv("VERSION") ?: "0.0.1-SNAPSHOT"
+description = "Simple QueryCompiler for Java"
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_21
+    targetCompatibility = JavaVersion.VERSION_21
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    antlr("org.antlr:antlr4:4.13.2")
+    implementation("org.antlr:antlr4-runtime:4.13.2")
+    testImplementation("org.junit.jupiter:junit-jupiter-api:5.11.4")
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.11.4")
+}
+
+tasks.withType<JavaCompile> {
+    options.encoding = "UTF-8"
+}
+
+tasks.test {
+    useJUnitPlatform()
+}
+
+
+tasks.generateGrammarSource {
+    maxHeapSize = "64m"
+    arguments = arguments + listOf("-visitor", "-long-messages")
+}

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.10-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists